Image Processing Apparatus and Image Processing Method

1. An image processing apparatus comprising: a generation unit which generates index image data that is image data including a plurality of pieces of thumbnail image data; an acquisition unit which obtains arrangement information indicating a position where the thumbnail image data is arranged in the index image data; a division unit which divides the index image data into a plurality of partial areas based on the obtained arrangement information, so that each of the plurality of pieces of thumbnail image data arranged in the index image data is not included in the same partial area with the other thumbnail image data; a calculation unit which calculates a histogram of a luminance value of pixels constituting the image data corresponding to the respective partial areas including the thumbnail image data; a correction unit which determines image correction characteristics for the respective partial areas based on the histogram, and, performs image correction to the image data corresponding to the respective partial areas by using the determined image correction characteristics; and an output unit which reconfigures the index image data using the image data corresponding to the respective partial areas subjected to the image correction by the correction unit, and, outputs the reconfigured index image data.

2. The image processing apparatus according to claim 1 , wherein the generation unit has an update unit which updates the index image data by replacing a part of the pieces of thumbnail image data included in the index image data with other thumbnail image data, and when the index image data is updated by the update unit, the division unit divides the updated index image data into the partial areas, the calculation unit calculates the histogram of the luminance value of pixels constituting the image data corresponding to the respective partial areas including the other thumbnail image data from among the partial areas, the correction unit determines the image correction characteristics of the respective partial areas including the other thumbnail image data based on the histogram, and, performs image correction to the image data corresponding to the partial area including the other thumbnail image data by using the determined image correction characteristics, the output unit reconfigures the updated index image data using (i) the image data corresponding to the partial area subjected to the image correction, and, (ii) the image data corresponding to the partial areas other than the partial areas including the thumbnail image data replaced with the other thumbnail image data, from among the pieces of image data corresponding to the partial areas used in the reconfiguration of the index image data by the output unit before being updated, and, outputs the reconfigured index image data.

3. The image processing apparatus according to claim 1 , wherein the correction unit performs image correction to pixels constituting the thumbnail image data in the image data corresponding to the respective partial areas by using the determined image correction characteristics.

4. The image processing apparatus according to claim 1 , wherein the image correction performed by the correction unit is gamma correction or color correction.

5. An image processing method comprising: a generation step of generating index image data that is image data including a plurality of pieces of thumbnail image data, by an image processing apparatus; an acquisition step of obtaining arrangement information indicating a position where the thumbnail image data is arranged in the index image data, by the image processing apparatus; a division step of dividing the index image data into a plurality of partial areas based on the obtained arrangement information, so that each of the plurality of pieces of thumbnail image data arranged in the index image data is not included in the same partial area with the other thumbnail image data, by the image processing apparatus; a calculation step of calculating a histogram of a luminance value of pixels constituting the image data corresponding to the respective partial areas including the thumbnail image data, by the image processing apparatus; a correction step of determining image correction characteristics for the respective partial areas based on the histogram, and, performing image correction to the image data corresponding to the respective partial areas by using the determined image correction characteristics, by the image processing apparatus; and an output step of reconfiguring the index image data using the image data corresponding to the respective partial areas subjected to image correction in the correction step, and, outputting the reconfigured index image data, by the image processing apparatus.

6. The image processing method according to claim 5 , wherein the generation step includes an update step in which the index image data is updated by replacing a part of the pieces of thumbnail image data included in the index image data with other thumbnail image data, and when the index image data is updated in the update step, in the division step, the image processing apparatus divides the updated index image data into the partial areas, in the calculation step, the image processing apparatus calculates the histogram of the luminance value of pixels constituting the image data corresponding to the respective partial areas including the other thumbnail image data from among the partial areas, in the correction step, the image processing apparatus determines the image correction characteristics of the respective partial areas including the other thumbnail image data based on the histogram, and, performs image correction to the image data corresponding to the partial area including the other thumbnail image data by using the determined image correction characteristics, in the output step, the image processing apparatus reconfigures the updated index image data using (i) the image data corresponding to the partial area subjected to the image correction, and, (ii) the image data corresponding to the partial areas other than the partial areas including the thumbnail image data replaced with the other thumbnail image data, from among the pieces of image data corresponding to the partial areas used in the reconfiguration of the index image data in the output step before being updated, and, outputs the reconfigured index image data.

7. The image processing method according to claim 5 , wherein in the correction step, the image processing apparatus performs image correction to pixels constituting the thumbnail image data in the image data corresponding to the respective partial areas by using the determined image correction characteristics.

8. The image processing method according to claim 5 , wherein the image correction performed in the correction step is gamma correction or color correction.